I didn't expect you to be able to finish World War IV in time for the end of the game. As ludicrous as Italian China is, I think you've earned it.
The only real way I've seen to make the U.K. not such an Industrial powerhouse is to ensure they are on the losing side of a Great War. Once the rebellions in India get going, the AI can't recover.
Fantastic lets play I must say, I'm glad I was able to watch it all. I hope for another lets play soon. Perhaps some one hard like the ottomans